| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [noun prp] once a | 13 |
|
| 2 | [prep] [noun prp] once a | 13 |
|
| 3 | to [noun prp] once a | 7 |
|
| 4 | to [noun prp] once a | 7 |
|
